1. Technical Field
This disclosure relates to a technology for outputting an image with less amount of coloring material.
2. Description of the Related Art
Some image processing apparatuses have a toner-save mode for outputting an image with less coloring material such as toner and ink, in addition to a normal-mode for generating and outputting higher-quality image data. The toner-save mode is selected when quality of output image is less emphasized because, for example, the output image is used just for checking its layout.
There are various methods of reducing toner consumption such as a method of reducing image density, a method based on a logical multiplication between a dithered image and a pixel-skip pattern, a method of using pulse-width modulation, and a method of controlling light-intensity for writing. According to these methods, density of an image to be output is lower, and therefore, the output image is not as good as an image that is output in the normal mode.
For example, Japanese Patent Application Laid-open No. H9-219790 discloses a conventional technology of reducing toner consumption by identifying edges in a bitmap image and reducing an amount of toner based on the identified edges. Japanese Patent Application Laid-open No. H7-107280 discloses another conventional technology of reducing toner consumption by detecting edges and processing a portion other than the edges in toner-save mode.
The conventional technologies require a printer having the toner-save mode. Moreover, when image data processed in the toner-save mode (hereinafter, “toner save-mode image”) is transmitted to an external device, the external device cannot display the toner save-mode image as the one in the normal mode (hereinafter, “normal-mode image”).